Saturn is famous for the intriguing rings that encircle it. As Saturn orbits the Sun, though, our view of its rings changes. Roughly every 15 years (halfway through Saturn’s almost-30-year orbit), Saturn’s rings appear edge-on, sometimes seeming to disappear altogether. Because many of Saturn’s moons orbit the planet in the same plane as the rings, they appear to cross in front of the planet during this time. On February 24, 2009, when Saturn’s rings were nearly edge-on, Hubble tracked four of Saturn’s moons as they passed across the face of the giant ringed planet.